Background

An expert panel was convened to evaluate evidence in an update and reaffirmation of the 2010 “ASCO/CAP Guideline Recommendations for Immunohistochemical (IHC) Testing of Estrogen and Progesterone Receptors (ER/PgR) in Breast Cancer.”

A new recommendation for laboratories to establish a specific standard operating procedure to ensure the validity of low positive (1-10%) or negative (0 or < 1%) interpretations and results. Correlation of ER staining with the histologic features (as well as attention to other standard quality control measures) is also recommended and unusual/discordant results worked up.

New reporting recommendations are made for cases with 1-10% ER expression to acknowledge the more limited data on endocrine responsiveness in this group and overlapping features with ER negative cancers. The status of internal controls should also be reported for cases with 0-10% staining (with a special comment for those lacking internal controls).

The utility of PgR testing continues to be largely prognostic in the ER-positive invasive cancer population, but testing using similar principles to ER testing is still recommended for invasive cancers.

The update recommends ER testing for patients diagnosed with ductal carcinoma in situ without invasion; PgR testing is optional.

We encourage laboratories to adopt these recommendations.

Guideline Information

Guideline status: ActiveOriginally published: June 2010Update published online ahead of print: January 13, 2020Update published in print: May 2020

Guideline Tools & Resources

The following tools and resources are available to help implement the guideline:

Joint Partners

American Society of Clinical Oncology

Additional Information

Accreditation Requirements and Proficiency Testing (PT)

While recommendations may be incorporated into future versions of the CAP Laboratory Accreditation Program checklists, the ER/PgR guideline update directs providers to follow their laboratory accrediting body’s guidelines and requirements.

Accreditation checklist requirements regarding ER/PgR assay validation, specimen fixation, and proficiency testing are available to CAP accredited laboratories through e-LAB Solutions Suite or can be purchased by non-CAP accredited laboratories.